27-07-2012, 01:34 PM
Design and Implementation
sql.ppt (Size: 219 KB / Downloads: 164)
An Overview of SQL
SQL stands for Structured Query Language.
It is the most commonly used relational database language today.
SQL works with a variety of different fourth-generation (4GL) programming languages, such as Visual Basic.
SQL is used for:
Data Manipulation
Data Definition
Data Administration
All are expressed as an SQL statement or command
SQL is a Relational Database
Represent all info in database as tables
Keep logical representation of data independent from its physical storage characteristics
Use one high-level language for structuring, querying, and changing info in the database
Support the main relational operations
Support alternate ways of looking at data in tables
Provide a method for differentiating between unknown values and nulls (zero or blank)
Support Mechanisms for integrity, authorization, transactions, and recovery